This invention relates to a fluid or liquid powered pump, and more particularly to such a pump which is particularly useful for injecting a liquid additive into a main stream of liquid flowing through the pump. For example, this invention has particular application for injecting a liquid deoderant or disinfectant into the water lines supplying flush water to a toilet or the like.
Recreational vehicles, such as motor homes, travel trailers, campers, boats, airplanes, and the like are oftentimes or usually equipped with a toilet which when flushed dumps the waste and the flushing water into an on-board holding tank. Periodically, the holding tank is emptied of its waste, but in the meantime a considerable quantity of waste may accumulate therein. The holding tank is oftentimes installed in the floor structure of the recreational vehicle and the toilet is connected directly to the holding tank (i.e., the toilet is located directly above the holding tank). The outlet of the toilet leads down to the holding tank so that waste falls by gravity into the holding tank. A normally closed slide valve or the like is provided in the outlet of the toilet which when closed prevents odors from within the tank from entering the living areas of the recreational vehicle. Typically, no sewer trap is provided between the holding tank and the toilet.
Such recreational vehicle toilets are provided with a flush water system for the purpose of rinsing out the toilet bowl after each use and for forcing the waste out of the toilet bowl. However, these recreational vehicle toilets are quite different from conventional flush valve toilets such as are used in most U.S. residences. Many residential flush valve toilets use from 4-7 gallons of water for flushing the toilet and a considerable volume of water is retained in the toilet bowl. However, in many recreational vehicle toilets, no water is retained in the bowl and only a small quantity (e.g., from about 1 cupful to several quarts) is required to flush the toilet. This, of course, is desirable because it significantly decreases the quantity of fresh water that must be stored on-board the recreational vehicle and it reduces the required capacity of the holding tank. Typically, one flushes the recreational vehicle toilet by actuating a valve (either a foot or hand operated valve) which permits a desired quantity of flushing water to enter the toilet and which also effects the opening of the outlet valve so as to permit the waste in the toilet bowl and the flushing water to enter the holding tank. After the flushing cycle is complete, the toilet valve will close isolating the holding tank from the interior of the recreational vehicle.
Oftentimes, recreational vehicle owners will pour a liquid or granular chemical (e.g., a deodorant or disinfectant) into the holding tank by dumping the additive into the toilet bowl. Typically, this additive is added to the holding tank after it has been emptied and after a small amount of fresh water has been added thereto so as to control odors emitted from the holding tank as waste accummulates therein. It is desirable to have a relatively high concentration of the additive in the holding tank in its initial stages of use so as to effectively control odors when the holding tank is nearly empty and as it is being filled. Of course, with this method of manually adding the additive to the holding tank, the entire amount of additive is placed into the tank before any waste is accummulated therein. In many cases, however, it is desirable to add additional quantities of a deodorant or the like to the holding tank after each use of the toilet thereby to add fresh deodorant or other additives to the tank so as to further aid in controlling odors. Of course, with prior manual systems for adding the additive to the holding tank, the recreational vehicle user would be periodically required to pour small amounts of the deodorant into the holding tank via the flushing the toilet. However, many recreational vehicle users would find this task unpleasant and others would simply forget to do it. As a consequence, noxious odors are oftentimes a problem in many recreational vehicles.
While certain known mechanical systems may be adaptable to inject a quantity of a liquid additive or the like into the holding tank of a recreational vehicle each time a toilet or other appliance is used, these other systems are complicated and expensive. Also, these prior automatic additive systems typically require the use of a vented additive storage tank or bottle. Of course, in a recreational vehicle, the use of such a vented additive bottle could lead to spillage of a liquid additive within the recreational vehicle during normal use of the recreational vehicle.
Among the several objects and features of the present invention may be noted the provision of a pump useful for injecting a liquid additive into a main stream of liquid wherein the pump is of simple construction and is powered solely by the flow of the main stream of liquid through the pump;
the provision of such a pump which when installed in a recreational vehicle toilet system is automatically operated each time the toilet is flushed so as to inject a quantity of suitable additive (e.g., a deodorant or disinfectant) into the flush water so that a fresh supply of additive is added to the holding tank each time additional waste enters the holding tank;
the provision of such a pump which adds a relatively large quantity of concentrated additive to the holding tank upon the first few or initial flush cycles of the toilet and which adds progressively weaker solutions on subsequent flushes so that the majority of a desired quantity of additive is added to the holding while the holding tank is mostly empty and so that additional quantities of the additive are added each time the toilet is flushed thereby to ensure a continuing fresh source of the additive;
the provision of such a pump which may be readily incorporated in a recreational vehicle during manufacture thereof, or which may be readily installed on existing recreational vehicles (i.e., retrofitted) by the recreational vehicle owner with only simple hand tools;
the provision of such a pump which operates satisfactorily over a wide range of pressures of the liquid flowing through the pump and which will operate in any position;
the provision of such a pump in which the supply of liquid additive is not vented so as to prevent the spillage of additive from the additive tank during normal usage of the recreational vehicle in which the system is installed;
the provision of such a pump which may be readily incorporated in virtually any liquid flow system so as to inject any liquid additive into a main stream of the liquid; and
the provision of such a pump which is of simple and rugged construction, which contains no moving parts, which is reliable in operation, and which is of low cost to manufacture.
Other objects and features of this invention will be in part apparent and in part pointed out hereinafter.